Traube reaction

The use of thiophosgene in Traube reactions has probably been limited by its relative inaccessibility but applications have been made under conditions analogous to those used with phosgene as in the preparation of the 2-methylthio-6-oxo-8-thioxopurine (284 Scheme... 

Alcohol. Traube Reaction. The Traube reaction (23, 28, 29) involves the conversion of ethyl alcohol, in the presence of added base, to methylenediisonitra-mine by nitric oxide. The structure of the product has been established by a single-crystal x-ray study. 

The Traube synthesis has proved to be compatible with many kinds of groups in the starting pyrimidine (R and R in 60), even with the thioxo (mercapto) and primary amino groups. Pyrimidine iV-oxides are also acceptable.Moreover, 8-azapurines with substitutents in the usually difficult 1 and 3 positions have been formed by Traube reactions (refs. 150 and 151, respectively). 2-Pyrimidyl-8-azapurines have also been produced in this way. The Traube reaction permitted amino-acid substituents (as R in 60) to retain full optical purity. Radioactive labeling survived well when a diaminopyrimidine, made in five steps from diethyl malonate-7- C, was cyclized. ... 

Stark, W., Kinkel, J., Michel, M., Schmidt-Traub, H., Micro reactor for electroorganic synthesis in the simulated moving bed-reaction and separation environment, Electrochim. Acta 48 (2003) 2889-2896. 

BHT (2,6-di-tert-butyl-4-methylphenol), a phenolic antioxidant, on reaction with NO under neutral conditions, results in scavenging of the potentially harmful NO via radical reactions [143]. Sodium phenolate under basic conditions undergoes a Traube-type reaction at the ortho-position to produce a cupferron derivative [144]. When the ortho-positions are sterically blocked and the para-position does not bear a proton, cyclohexadienone diazeniumdiolates may be formed (Scheme 3.12) [145]. 

As to catalytic reactions in homogeneous media, Moritz Traube found in his studies of the oxidation of hydrogen iodide by hydrogen peroxide in aqueous solution, that the catalyst ferrous sulfate is activated by copper sulfate (5). As to the magnitude of such effects, Price stated in 1898 (6) that the simultaneous action of iron and of copper compounds on the reaction between persulfate and hydrogen iodide causes an unexpected acceleration of the reaction, which is more than twice as great as the acceleration calculated as an additive effect of the two single catalysts. However, effects were also observed of the opposite kind,... 

The sodium salt of methylenedi-isonitramine was prepared by Traube [62] from acetone and nitric oxide in the presence of sodium alcoholate according to the following chain of reactions ... 

The addition of a carbamon to an epoxide was first described in 1899 by Traube and Lehman, 7M who condensed ethylene oxide with diethyl BodiomaJonate. Subsequent work by these and other inveeti gators124-18M-18M 17fl established that any of three products may be formed depending on the particular reaction conditions employed (Eq. 867), At moderate temperatures equimolar quantities of reactant ... 

This conclusion of Traube s is sufficient for not accepting oxidation by molecular oxygen for the primary reaction. In this reaction, H202 and other peroxides are intermediate products which, in accordance with modem terminology, may act as oxidation initiators and inducers. 

Schmidt-Traub, H., Gorak, A. (Eds.) Integrated Reaction and Separation Operations. Modelling and experimental validation. Springer, Berlin, 2006. 

The Traube synthesis still remains valuable as a route to the synthesis of specific purines. The method has been used to record the first synthesis of hypoxanthine-/V(7)-oxide (30) by reaction of 6-chloro-5-nitro-4(3H)-pyrimidinone with A-(4-methoxybenzyl)phenacylamine (Scheme 18) <92CPB612>. The same authors also report analogous syntheses of 8-methylguanine-7-oxide and its 9-arylmethyl derivatives, and guanine-7-oxide and some 9-substituted derivatives (92CPB343, 92CPB1315). 

According to Traube s theory, the first-named reaction proceeds as follows ... 

Moritz Traube 4 rejected this explanation on the ground that carbon monoxide does not decompose steam at the temperature of the electric spark, for reaction (i) is reversible and under these conditions proceeds m the direction right to left. 

This objection, however, is not valid, for, whatever the temperature, the law of mass action requires that definite, even if small, amounts of carbon dioxide and hydrogen shall exist in equilibrium with the other gases in the system. Hence, if for any reason the partial pressure of the carbon dioxide or hydrogen falls below that required for equilibrium, it is always possible for reaction (i) to proceed, even at high temperatures, in the direction of left to right. Traube explained the reaction, however, on the assumption that the function of the steam is to unite with one atom of the oxygen molecule, the second atom being occupied in the oxidation of the carbon monoxide. Thus... 

Substituted purines may arise in mixtures with 9-substituted derivatives from direct alkylation of purine anions. They are best prepared however by Traube syntheses. Thus formylation of 4,5-diamino-6-benzylthiopyrimidine and ethylation of the formyl derivatives gave a formamidopyrimidine which readily cyclized to 6-benzylthio-7-ethylpurine in the presence of potassium carbonate (B-68MI40901, p. 31). The derivative is clearly a ready source of 7-substituted adenines by reaction with ammonia or amines, or of 7-substituted purines by dethiation with Raney nickel. 7-Methylguanine has also been obtained from 7-methyl-guanosine, sodium borohydride and aniline at pH 4.5 (B-78MI40903, p. 615). 

Alkoxypurines, especially 6-alkoxypurines, are normally best prepared by reaction of a chloropurine with a sodium alkoxide as with 6-methoxypurine from 6-chloropurine and sodium methoxide (57CB698). However Traube syntheses have also been used in the preparation of 2-methoxypurine from 4,5-diamino-2-methoxypyrimidine and formic acid (54JCS2060) or 2,6-dimethoxypurine from the corresponding dimethoxypyrimidine (54JA5087). 8-Ethoxypurine has also been usefully prepared from 4,5-diaminopyrimidine and tetraethoxymethane (74JCS(P1)349>. 

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